Floor sander



F. HE DEMARK moon SANDER Filed Sept. 3, 1945 I Nov. 25, 1947.

2 Sheets-Sheet 1 4 IINVENTOR.

J/LMQ I Nov. 25, 1947. F. i-IEDEMARK FLOOR SANDER Filed Sept. 8, 1945 2Sheets-Sheet 2 INVENTOR.

BY 3M Patented Nov. 25, 1947 FLOOR SANDER Fred Hedemark, ProspectHeights, 111., assignor to Skilsaw, Inc., Chicago, 111., a corporationof Delaware Application September 8, 1945, Serial No. 615,205

8 Claims.

The present invention relates to improvements in floor sanders or thelike.

Floor sanders have been manufactured and sold heretofore for finishingnew floors and refinishing old floors in homes, factories, hospitals andofiices. These machines generally have been heavy and cumbersome,requiring the services of an expert operator. Machines of this type attimes in the past have been rented to home owners who wished to finishtheir own floors but the weight of the machines, the difficulty ofcarrying these large machines, the difficulty of fitting them into arenters. auto, and the necessity for expert operation has tended to slowthis field of rental machines and has forced the home owner in mostinstances to rely upon the services of a contractor.

One of the objects of the present invention is to provide a floor sandermeeting the special requirements of the rental field.

Another object is to provide a sander that is compact and easy tooperate.

Another object is to provide a machine that is relatively light for thework to be performed and easily carried from. car to house or around ahouse or store.

A further object is to provide a tool that will not gouge floors nearwalls under inexperienced operation and one that may be easilymaintained or adjusted by a local dealer or home owner.

Yet another object is to provide a machine that can be carried,maintained and operated by an inexperienced person.

Various other objects of this invention will be pointed out hereinafterwith reference to the drawings.

In the drawings:

Fig. 1 is a View in side elevation of the machine with a portion of themain housing cut away.

Fig. 2 is a view in front elevation of the machine.

Fig. 3 is a view in rear elevation with a portion of the housing cutaway Fig. 4 is a view in enlarged detail of the carrying handle for themachine.

As exemplified herein, the invention is disclosed in connection with amachine for sanding floors. The invention was created having in mind aninexperienced operator who might be performing the work onlyoccasionally, who probably is not used to long hours of work of thistype and ordinarily might tire quickly or be likely unintentionally tocause unwanted damage to floors or machines. For these reasons theinvention relates to improved structure that enables the machine to bemade most compact and light in Weight. Most structures heretoforethought mandatory has been omitted. For instance heretofore shafts havebeen mounted for swinging movement away from each other for belttightening or releasing purposes. This has meant enlarged castings andextra mechanisms. Fixed centers on shafts, a single driving belt andnovel tightening means for the belt without altering these centers withrespect to each other has decreased the size and weight of the machineand made adjustment most simple.

Novel carrying means has been installed, normally hidden and out of theway, that permits the operator to carry the machine from place to placewithout undue strain on himself and less likelihood of damage to themachine. The occasional operator is never at a loss to know how tohandle or carry the machine.

In the momentary change of direction of the former machines adjacentwalls or similar obstacles, the driven abrasive-covered drum tended togrind, sand or gouge a piece from or a groove in the floor that was mostdifiicult to remove. An experienced operator, by manual manipulation ofthe handle of the machine, could compensate for this gouging. Aninexperienced operator might find that his operation of the usual floorsander gouged the entire floor area'adjacent the walls. Through thepresent invention the sanding drum is automatically lifted from thefloor adjacent obstacles such as walls in a feathering action actuallypreventing this gouging, even though the machine is carelessly operated.

With reference to the drawings the machine as shown includes a mainframe I0 upon or to which the various mechanisms and structure aremounted. A motor housing I2 is suitably mounted to the frame in anydesired manner and encloses a motor (not shown) having a driving shaftl4 carrying a motor sheave IS. A handle l3 for the machine is likewisesuitably mounted in a socket I 5 attached to said frame.

A drum shaft I8 carrying a drum sheave 20 is likewise rotatably mountedin said frame In and 'mally rests on a floor surface 24.

has keyed thereto a sanding drum 22 that nor- Supporting wheels 25 forthe machine are rotatably mounted on the frame l0 and normally carry thegreater part'of the weight of the machine.

Where it is desired to pick up the dust created by the action of thesanding drum on a surface 24, a further rotatable shaft 26 may berotatably mounted in said frame l0 carrying an exhaust fan 28 at one endthereof and a fan sheave 34 at the other end and in substantialalignment with the motor and drum sheaves. An exhaust chamber 32surrounds said fan while an exhaust conduit 34 leads from adjacent thedrum Ill, through fan chamber 32 to exhaust pipe 36 and thence to a bag(not shown) or other receptacle for the dust.

A driving belt 38 passes around the driving motor sheave I6, drum sheave20 and fan or idler sheave 2B and drives them at speeds that may bepredetermined for no load or normal load by fixing the size of thesheaves. The centers or axes of these shafts may be fixed relative toeach other and as close to each other as possible for compactness. Ifthese axes were made adjustable with respect to each other fortightening belt 38, the housings l2, belt guard 49 and the motor anddrum guard 42 would have to be considerably enlarged to allow one ormore of these shafts to be adjustably swung away from the others to takeup slack in the belt as it wears and elongates. Two methods ofadjustment have been used heretofore. One was to swing the entire motorassembly up and away from the other shafts to tighten the belt whileanother was to insert an additional movable idler pulley for thispurpose. The extra structure involved for thus permitting relativemovement of the shafts added weight and expense to the machine. Instead,applicant simplifies this materially by making one of the sheaves suchas fan sheave 31] (Fig. 3) adjustable and in the nature of a splitpulley,

As shown, the split pulley may comprise an inner flange member 44 formedon an exteriorly threaded hub 43 keyed to the shaft 26. An outer flangemember 42 interiorly threaded, may be screwed over hub 43 to vary thedistance between flanges and thus form a variable or adjustable inwardlyconverging slot or guideway for the belt 38 that causes said belt totravel adjacent to or away from hub 43 and the axis of shaft 26 in itspath around the sheave and thus enlarge or restrict the path of travelof said belt.

By tightening the outer portion or flange 42 of the sheave over thethreaded hub 43 and toward the rear portion 44, the belt 38 is caused toride higher in the slot formed thereby thus enlarging the path of thebelt and tightening it as it wears or stretches. The slight alterationnecessary to tighten the belt does not serve to appreciably change therelative speed of the rotation of the shafts but acts substantially onlyto tighten belt 33.

The frame I is open in front to permit access to the drum 22 forchanging abrasive paper. This opening is normally closed by a cover 46hingedly mounted to the housing to swing upwardly and to be closed bygravity to shut in dust and protect the drum from obstacles. Whenclosed, it further protects walls and the sides of door openings fromdamage from the drum.

Within the opening to the drum, a carrying handle for the machine may bemounted. As shown, a bracket 41 having depending lugs 43, 49 is weldedor otherwise secured to frame l6 within the opening. A shaft 53 ismounted through openings in said lugsand a substantially U-shaped handlemember 52 is mounted over said shaft. This handle member is mounted toswing forwardly through said opening into operative position (dottedlines, Fig. l) when cover member 4!; is raised, through the action ofspring 54 suitably mounted on shaft 50.

To prevent the handle from dropping onto the drum upon a loosening ofspring 54 or its breakage, a stop means may be provided as by continuingthe ends of the U-shaped handle member rearwardly of their mounting asat 55 and providing a stop member 58 on the frame It! to positivelyprevent further downward movement of the handle beyond a. spacedposition from the drum as shown. The handle member 52 engages the frameI0 in its operative position and may be used to lift the entire machinefrom the floor with comfort to the hand. To prevent injury to the coverhinge 59 or the housing l2, a raised lug 50 may be incorporated on thehandle member to contact the frame l0 when in operative position andhold the handle member in spaced relation to the remainder of themachine and so the lift on the handle is from the main frame itself.

Spring member 54 preferably is of such force that the weight of thecover member 48 will cause the handle member yieldingly to withdraw intoits inoperative position ready for release when the cover is raised.Upon lifting the cover 46 the handle is thus positively forced intooperative position extending outwardly through the drum opening and isyieldingly pressed into inoperative position within the frame upondropping the cover.

With reference to Figs. 1 and 2 one embodiment of the automatic lift forthe drum is disclosed. As shown, this includes an arm 62 pivoted to theframe l0 through a screw 63 and held free of the frame through a spacingmember 64. At its lower end an axle shaft is mounted at right angles tothe arm and a wheel 68 preferably of rubber or other resilient materialis mounted thereover and held in place by a cap nut 69. The belt guardcasting 40 is cut away as at H to permit the arm and its roller toextend outwardly in front of the machine.

When roller 68 strikes a quarter round or wall, a continuing forwardmovement of the machine causes the forward end of the machine to riseupwardly, lifting the drum from the surface 24 as arm 62 is forcedtoward a vertical position. The arch-like rise of the drum through theaction of arm 62 stimulates the feathering action of a professionaloperator obtained through proper lpessure and manipulation of themachine handle Without this drum lifting member, an inexperiencedoperator may permit the cover 46 to bump or strike a wall without agradual lift of the drum from the surface 24. This slight pause for achange of direction permits the drum to sand longer in this spotadjacent the wall than it does on the remainder of a floor. Unsightlygouging or grooving results in the surface at this spot. To preventscratching the wall by the cover 46 and to prevent the arm from strikingthe drum or drum pulley a stop means may be used that halts the machine,except for roller 68, in spaced relation to the wall. As shown a stopmember or pin 70 is mounted to the frame 10 behind the arm 62 and in aposition such that the arm 82 may impart a lifting feathering action tothe drum but will not be permitted to pass sufficiently beyond deadcenter as to strike the revolving drum, shaft or sheave. It is alsomounted sufficiently forward to permit the arm to lift the drum but toprevent the cover 46 from coming into contact with a wall The arm andstop members thus act as a limiting means or bumper for the machine.

, Upon backing the machine from the wall, the arm 62 likewise permits areverse. feathering action for the drum and preferably is positively butyieldingly pressed from its lifting position into the inoperativeposition as shown in Fig. I through the use of a spring 12 that may bemounted at one end to the frame If! as at 14 and caused to yieldinglypress the arm 62 forwardly at its free end.

Various modifications coming within the spirit and scope of theinvention will be apparent to those skilled in the art upon a study ofthis specification, the drawings and attached claims.

I claim:

1. The combination in a floor sanding machine, including a frame and apower operated sanding drum rotatably mounted in said frame of carryingmeans for said machine, including a handle member pivotally mounted onsaid frame, resilient means for pressing said handle into operativeposition, a cover member for said drum hingedly mounted to said frameadjacent to said handle, said cover when closed holding said handleyieldingly confined therewithin in inoperative position and said coverwhen open permitting said handle to assume its operative position.

2. The combination with a fioor sanding machine having a frame and apower operated rotatable sanding drum mounted therein, of carrying meansfor said machine, including a cover member hinged to said frame andenclosing a portion of said drum when closed, a handle member mountedfor limited movement to said frame within the confines of said coverwhen in closed position, said handle member being movable beyond theclosed confines of said cover member to an operative position forgrasping by a hand when said cover member is in opened position andmeans for positively moving said handle member into operative positionupon the opening of said cover member.

3. The combination as defined in claim 2 wherein said cover member ishinged to said frame for upward swinging movement and may yieldinglypress said handle member inwardly within the closed confines of saidcover member through the weight of the cover alone.

4. The combination as defined in claim 2 wherein a stop means isprovided to prevent contact of said handle member with the sanding drumwhen within the closed confines of the cover member.

5. In a floor sanding machine the combination of a frame, a power drivensanding drum rotatably mounted in said frame, said frame being open topermit access to said drum, a cover member hinged to said frame to closesaid access opening, a handle member for said machine, pivotally mountedto said frame between said drum and said cover when the latter isclosed,

6 spring means mounted adjacent to said handle member tending to presssaid handle member beyond the closed position of said cover member, saidspring means being sufficiently yielding to permit said handle member toswing inwardly under the weight of said cover member in closing.

6. In a fioor sanding machine, the combination with a frame having apower driven drum mounted thereon at its forward end for finishing floorsurfaces and frame supporting means positioned rearwardly of said drum,of means for lifting said drum from an operative position against thefloor surface, said means including a lifting arm pivotally mounted atone end adjacent the forward portion of said frame and extendingdownwardly and forwardly to a position adjacent the fioor surface infront of said drum, said arm being free at its other end and beingadapted upon being halted as by striking a wall or the like, with acontinuous forward movement of machine, to tend to assume asubstantially vertical position, lifting said frame and raising saiddrum from its operative position against a fioor surface.

7. The combination as defined in claim 6 wherein spring means is mountedon said frame to cooperate with said arm in tending to hold said arm inits position adjacent the floor surface in front of said drum, andwherein said spring means yieldingly permits said arm to assume asubstantially vertical position on being halted by an obstacle upon acontinuous forward movement of the machine.

8. The combination as defined in claim 6 wherein a stop member ismounted on said frame to prevent the machine from passing forwardly ofsaid arm when raised thereby and spring means is mounted on said frameto cooperate with said arm to positively return the same to its positionadjacent the floor surface in front of said drum upon removal of the armfrom contact with said wall.

FRED HEDEMARK.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,752,965 Robertson Apr. 1, 19301,934,814 Myers Nov. 14, 1933 2,087,642 Forsberg et al July 20, 19372,112,157 Hatcher Mar. 22, 1938 2,118,818 Okun May 31, 1938 2,262,197Otto et a1 Nov. 11, 1941 2,323,082 Ballard June 29, 1943 2,325,649Batterson Aug. 3, 1943

